Bicknell v Pickard  centered around to what extent the plaintiff’s psychiatric illnesses were caused by a motorcycle collision between the plaintiff and the defendant, and the extent to which his residual injuries and psychiatric illness caused economic and non-economic loss.  Several expert witnesses were called by both sides to aid the court in determining these issues.
In his judgement, McCann DCJ concluded that considerable portions of the expert evidence provided by an occupational therapist engaged by the plaintiff were inadmissible, or else “…of such minimal value as to be put to one side”.  The criticisms made by McCann DCJ serve as key lessons for legal counsel to keep in mind when reviewing expert evidence.
The Expert’s Qualifications
The expert who wrote the report in question had over 26 years of industry experience as an occupational therapist. She was working as a lecturer in Occupational Therapy and had completed a Bachelor of Applied Science (Occupational Therapy) at the University of Sydney in 1993. There were no criticisms made of her qualifications, or of her general suitability to provide expert evidence in this matter.
1. Experts Should Avoid Providing Layperson Evidence
In his judgement, McCann DCJ stated that the purpose of an expert occupational therapist was to “identify and explain any functional needs which the plaintiff may have which are so…specialised as to be beyond the fact-finding capacity of a layperson”.  The occupational therapist in this matter provided ‘expert’ opinion in areas that required no expert explanation at all, such as the hours that should be assigned for gratuitous services. McCann DCJ criticised this “forensic trend”  of experts going beyond their expert purview and making findings of fact that a layperson could make, saying:
“Fact-finders are perfectly capable of receiving, understanding, assessing and making findings about evidence concerning a wide range of functional activities (such as gardening and cleaning) that do not require expert elucidation. The fact that science is capable of explaining or dealing with a normal activity of daily living does not meant the trier of fact should receive the science”. 
A submission that this was merely a convenient way of collating evidence was rejected – due to the “so-called evidence” in reality being a “conclusionary submission” and therefore being “inadmissible”. Thus, it must be ensured that expert witnesses only provide expert comment on areas that require expert opinion, or else risk having these elements of their report rejected.
2. Experts Must Base Opinions on Evidence
As stated in Makita v Sprowles, an expert must expose their reasoning process, with it being insufficient for an expert to say that their basis of their opinion is merely because they are an ‘expert’. As stated by Heydon JA, expert opinions: “…Must be identified and proved in some other way; it must be established that the facts on which the opinion is based form a proper foundation for it…”  In this matter, the occupational therapist was unable to explain the basis of her reasoning for several of her claims to the judge’s satisfaction, leading to these claims being rejected. 
It was also observed by McCann DCJ that a number of assumptions made by the occupational therapist were not based in evidence and therefore verged “on advocacy”. It is of the utmost importance that experts remember their paramount duty is to the court and not to the party that has engaged them, as stated in the Expert Witness Code of Conduct. Appearing to be acting as an advocate can cause a court to discount a report due to a lack of credibility.
It is important that when reviewing an expert report, it is ensured that the expert adequately explain how their conclusions are reached, to avoid evidence being discounted due to lack of reasoning. Likewise, it is vital that an expert focuses on the facts in the matter and avoids giving the appearance of being an advocate. An appearance of advocacy can lead to an expert’s integrity being drawn into question and in the most extreme cases can lead to whole reports being rejected by the court.
3. Expert Speciality Must be Considered
McCann DCJ preferenced the expert evidence provided by a medical practitioner on the same topic, criticising the occupational therapist’s view that her expert opinion was superior, due to her taking a “…holistic view”.  Although McCann DCJ observed that an occupational therapist’s opinion may be valued over a doctor’s in regard to identification and treatment of “very specific functional needs”. he did not accept that an occupational therapist’s ‘medical’ opinion could be preferred to a doctor who practiced in a corresponding medical field. The judge commented that only in exceptional circumstances could an occupational therapist’s medical opinion be preferred to that of a doctor.
It is important for lawyers to be aware of how an expert’s opinion is likely to be perceived by the court. In general, it is important to engage an expert witness with the highest level of speciality and expertise in a subject area. For instance, in a matter is pertaining to a brain injury, a specialist neurosurgeon would likely have their evidence preferred over that of a general practitioner.
Although the plaintiff was eventually awarded significant damages in this case, McCann DCJ’s comments regarding the expert’s evidence are useful reminders of the limits of expert evidence, and things to keep in mind when reviewing the evidence provided by an expert witness.
It is advisable to ensure that expert witnesses only provide expert opinion within their areas of expertise, and not merely make comment on things that any layperson could provide an informed opinion upon. Lawyers should make sure that their experts support any claims they make with evidence, and that the significance of their expert’s evidence is not overstated. They should be careful when drafting questions in their letter of instruction that they don’t ask questions that will cause the expert to offer opinions they are not qualified to make.
Through keeping the above points in mind, lawyers can help ensure that their expert’s evidence is well received by the court.
  WADC 174
 Ibid at Bicknell v Pickard  WADC 174 at .
 Ibid at .
 Ibid at 
 Ibid at .
 Makita (Australia) Pty Ltd v Sprowlesa at .
 Above n. 1 at .
 Ibid at